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From: mjm@oliven.olivetti.com (Michael Mammoser)
Newsgroups: rec.birds
Subject: Re: What is this bird??
Message-ID: <48269@oliveb.olivetti.com>
Date: 21 Sep 89 01:35:53 GMT
References: <3791@helios.ee.lbl.gov> <48214@oliveb.olivetti.com> <3192@nmtsun.nmt.edu>
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In article <3192@nmtsun.nmt.edu>, john@nmtsun.nmt.edu (John Shipman) writes:
 > 
 > While we're on the subject of nasty field identification
 > problems, how about hybrids?  The Christmas Bird Counts
 > from the northern Pacific coast in the last few years
 > often list more Glaucous-winged x Western Gulls than
 > either of the unhybridized species.  How are they
 > calling this form?

	I assume that you mean "how are they identifying this form".
I, personally, haven't had the guts to claim that I've seen one, but
it seems that the ID is based on the gray mantle/wing and the dark
primary tips being intermediate in color between the two. The two birds
should be quite similar in other field marks (i.e. size, bill shape,
leg color, etc.). You then have a bird with a mantle/wing color a
darker shade of gray than a Glaucous-Winged but lighter than a Western,
and the primary tips a dark brown or dark gray but not quite the black
of a Western. As far as identifying a juvenile; I don't know. I would
guess that the increase in the reported numbers is probably due to an
increased ability of observers to identify this hybrid.

	Speaking of hybrids, I've seen a couple of interesting ones
in recent years. A few years ago I was at the Palo Alto Baylands around
the beginning of the year and saw what I'm sure was a Northern Shoveler
x Blue-Winged Teal hybrid. The bird had a bright, distinct white crescent
in front of the eye (typical of BWT). This was not the fuzzy, indistinct
crescent seen in juvenile and eclipse male Northern Shovelers. It had a
dark brown crown separated from the rest of the head by a sharp line of
contrast (typical of BWT). The rest of the head and neck was an iridescent
green (typical of NS). It had a pale yellow eye (typical of NS). The breast
was densely marked with small spots on a light brown or tan ground color
(typical of BWT). The spotting continued down the sides, with a small
patch of chevron-like marks on the upper-rear flank (typical of BWT), but
the ground color had changed to a dark orange (typical of NS). The bill
was long and spatulate, and the bird was feeding at the edge of the 
water by sieving water through its bill (typical of NS). This was easily
the most unusual duck I have seen.

	Another hybrid that has been around the Baylands and Charleston
Slough for a couple of years, and seen by a number of people, is a
Snowy Egret x Little Blue Heron. The bird looks a lot like a Snowy Egret
except that the upperparts are marked with gray blotches and the legs
are a more uniformly colored gray or green. When first seen a few years
ago, the bird was identified as a juvenile Little Blue Heron. This is
understandable, considering that Little Blues are seen sporadically and
have recently been confirmed as breeders in the South Bay. The ID was
further compounded by the fact that the bird had yellow lores and the
first edition of the National Geographic Society Field Guide to the
Birds of North America shows juvenile Little Blues to have yellow lores.
Someone, who evidently had experience with Little Blues, indicated
that they have grayish lores in all plumages (this is shown correctly
in the second edition of the NGS field guide). This field mark has
been used to justify the hybrid status of the bird (along with the fact
that the bird's plumage hasn't changed from its blotchy gray on white
in a number of years).

	Any other interesting hybrids out there?

Mike